The invention relates to a mower that utilizes a reel blade and bed knife for cutting grass and the like. One of the primary problems in the past with reel blade type mowers is the constant adjustment required between the blades and the bed knife to insure proper cutting and to reduce excessive wear on the blade surface. In most mechanical reel blade mowers, the spatial relationship between the bed knife and the reel blade cutting edge is mechanically fixed by moveable, threaded connectors, that provide an adjustable but fixed contact pressure. Vibration, debris and mower movement usually change the contact pressure to an undesired value quite rapidly. To achieve consistent, proper adjustment in a conventional mechanical reel blade system, a person well versed in blade adjustment systems would have to constantly adjust and readjust the pressure between the blade and the bed knife. Ideally a light contact pressure is desireable.
Attempts have been made in the prior art to solve certain problems related to bed knife and reel blade wear and adjustment. For example in U.S. Pat. No. 2,896,390 issued to Cunningham, an automatic equalizer adjustment mechanism is disclosed for reel type lawn mowers. The purpose of the system described therein is to provide a movable bed knife that is counter-balanced by spring tension in engagement with the reel blade. Unfortunately, the problems in conventional systems in which the adjustments change due to the vibrations, rocks, or other debris also will affect Cunningham's automatic equalizer adjustment mechanism, thus still requiring adjustment to maintain the proper pressure along the bed knife. Another drawback is the complexity of the Cunningham system and the fact that it really does not provide self-adjustment or automatic adjustment of proper bedknife/reel blade contact pressure.
The problems of adjusting a single conventional reel blade mower (which are discussed in Cunningham's disclosure) are magnified at the commercial level when gangs of reel blade mowers are employed for cutting large grass areas such as golf courses. In such gangs of mowers, seven to nine reel blade mowers are not uncommon which thus requires seven or nine separate adjustments, each of which may need readjustment in a matter of minutes.
The present invention eliminates all mechanical adjustments between the bed knife and the reel blade, including rigid mechanical linkage heretofore known which required constant adjustment (or if improperly adjusted, resulted in undue wear to the system).
Another problem experienced with the fixed, mechanical reel blade/bed knife adjustment systems is that since the reel blade is mechanically coupled to the bedknife in a fixed relationship, debris encountered by the rotating blade can cause destruction of the blade by forcing debris between the blade and the bed knife. Improper mechanical adjustment can also warp the bed knife or the blades.
And yet another problem found in the fixed reel blade/bedknife mechanical systems is that for ideal mowing situations, the reel blade and bed knife should be adjusted differently, depending upon the heaviness of the cutting load or the thickness of the grass. Prior art mechanical systems had no provisions whatsoever for adjustment to compensate for different cutting loads other than a readjustment on site.
The present invention overcomes the problem of adjustment for different cutting loads by virtue of the fact that Applicant has determined that a floating reel blade, disposed at a proper pivot angle will cause the reel blade to bed knife contact pressure to increase (or decrease) depending upon the particular load. As far as potential debris damage, the floating reel blade will raise upwardly when contacting debris, allowing debris to pass through the lawn mower without destroying the blade.